Late Ordovician Konservat-Lagerstätten in Manitoba

Fossils from the Airport Cove site, part 1: spectacular examples of dasycladalean green algae on bedding plane surfaces (The Manitoba Museum, MM B-339, B-340).

Canada is remarkably rich in Konservat-Lagerstätten, sites at which unusual fossils are preserved. For the past while, Dave Rudkin and I have been co-editing a series for Geoscience Canada called Great Canadian Lagerstätten, which compiles reviews of these sites, covering many intervals from the geological record. The third paper in the series is based on our own research, describing the fossils from three unusual localities in central and northern Manitoba. Together with our co-authors, we have had a lot of fun putting this together: it was interesting to have the chance to assess the state of our “art”, to see where we really are with our research. We have learned a lot about these fossils, but still miles to go before we put this project to bed.

Fossils from the Airport Cove site, part 2: (c) Articulated scolecodont apparatus (jaws of a polychaete worm)(MM I-4062). (d) Large phosphatic or chitinophosphatic tubes of uncertain affinity (MM I-4061). (e) Finely preserved organic eurypterid cuticle (MM I-4063).

The abstract of the paper follows below. If you are interested in downloading a pdf of the entire paper, it can be found here.

Konservat-Lagerstätten, deposits in which soft-bodied or lightly sclerotized fossils are preserved, are very rare in Ordovician strata. Three significant sites are known from Upper Ordovician rocks in Manitoba: at Cat Head – McBeth Point, William Lake, and Airport Cove. These sites are in two distinct sedimentary basins: the former two are in the Williston Basin, while the latter is in the Hudson Bay Basin. All three sites contain marine fossils, but each has a different assemblage that contributes a distinct piece of the diversity picture. Important groups represented at one or more of the sites include seaweeds (algae), sponges, cnidarian medusae (jellyfish), conulariids, trilobites, eurypterids, xiphosurids (horseshoe crabs), and pycnogonids (‘sea spiders’). The different biotas reflect depositional conditions at each site. Many of the fossils are unknown elsewhere in the Ordovician at the family level or higher. The province of Manitoba therefore makes a significant contribution to knowledge of Late Ordovician biodiversity.

Fossils from the Airport Cove site, part 3: (f) Partial eurypterid abdomen (MM I-4586). g. ‘Head’ region of eurypterid-like arthropod (MM I-4064A). (h) The holotype specimen of the xiphosurid (horseshoe crab) Lunataspis aurora; note the preserved eye and dark-stained areas (MM I-4000). (i) This degraded example of L. aurora is surrounded by a halo of dark staining, possibly the result of postmortem decomposition of soft tissue and leakage of body fluids (MM I-4585).